C# 非模态窗体（show）实现模态窗体（ShowDialog）的效果

时间：2011-03-21 来源：许明吉博客

模态窗体（ShowDialog）打开后，后面的主窗体就不能做任何操作了。

本博客要实现非模态窗体（show）实现模态窗体（ShowDialog）的一些效果（主窗体关闭，子窗体也要关闭。子窗体只能打开一个。）

同时，保留非模态窗体的一些特性（主窗体和子窗体都能操作，比如文本的书写等）。

现实的一些用处：

1、比如要在主窗体中写已有的内容，用子窗体显示这些已有的内容（一般信息比较多，无法在主窗体中用某个空间显示完全）以供参考。

2、直接点击子窗体中的信息，在主窗体中显示出来。

等等

代码如下：

FormA----主窗体

FormB----子窗体

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using System;   
using System.Collections.Generic;   
using System.ComponentModel;   
using System.Data;   
using System.Drawing;   
using System.Text;   
using System.Windows.Forms;   
  
namespace BasicWindowsApplication   
{   
    public partial class FormA : Form   
    {   
        FormB formB = null;   
  
        public FormA()   
        {   
            InitializeComponent();   
        }   
  
        private void button1_Click(object sender, EventArgs e)   
        {   
            if (formB == null)   
            {   
                formB = new FormB(this);//这一步很重要   
                formB.CloseFrm += new EventHandler(frmA_CloseFrm);   
                formB.Show();   
            }   
            else  
            {   
                formB.TopMost = true;   
            }   
               
        }   
  
        /// <summary>   
        /// 窗体关闭事件   
        /// </summary>   
        /// <param name="sender"></param>   
        /// <param name="e"></param>   
        public void frmA_CloseFrm(object sender, EventArgs e)   
        {   
            formB = null;   
        }    
  
        /// <summary>   
        /// 窗体关闭事件   
        /// </summary>   
        /// <param name="sender"></param>   
        /// <param name="e"></param>   
        private void FrmA_FormClosed(object sender, FormClosedEventArgs e)   
        {   
            if (formB != null)   
            {   
                formB.Dispose();   
            }   
        }   
    }   
}  
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace BasicWindowsApplication
{
    public partial class FormA : Form
    {
        FormB formB = null;

        public FormA()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (formB == null)
            {
                formB = new FormB(this);//这一步很重要
                formB.CloseFrm += new EventHandler(frmA_CloseFrm);
                formB.Show();
            }
            else
            {
                formB.TopMost = true;
            }
            
        }

        /// <summary>
        /// 窗体关闭事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        public void frmA_CloseFrm(object sender, EventArgs e)
        {
            formB = null;
        }

        /// <summary>
        /// 窗体关闭事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void FrmA_FormClosed(object sender, FormClosedEventArgs e)
        {
            if (formB != null)
            {
                formB.Dispose();
            }
        }
    }
}

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using System;   
using System.Collections.Generic;   
using System.ComponentModel;   
using System.Data;   
using System.Drawing;   
using System.Text;   
using System.Windows.Forms;   
  
namespace BasicWindowsApplication   
{   
    public partial class FormB : Form   
    {   
        FormA formA;   
        public event EventHandler CloseFrm;   
  
        public FormB(FormA frm)   
        {   
            formA = frm;   
            InitializeComponent();   
            this.FormClosed += new FormClosedEventHandler(FrmB_FormClosed);   
        }   
  
        /// <summary>   
        /// 窗体关闭事件   
        /// </summary>   
        /// <param name="sender"></param>   
        /// <param name="e"></param>   
        void FrmB_FormClosed(object sender, FormClosedEventArgs e)   
        {   
            if (CloseFrm != null)   
            {   
                CloseFrm(sender, e);   
            }   
        }   
    }   
}  
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace BasicWindowsApplication
{
    public partial class FormB : Form
    {
        FormA formA;
        public event EventHandler CloseFrm;

        public FormB(FormA frm)
        {
            formA = frm;
            InitializeComponent();
            this.FormClosed += new FormClosedEventHandler(FrmB_FormClosed);
        }

        /// <summary>
        /// 窗体关闭事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void FrmB_FormClosed(object sender, FormClosedEventArgs e)
        {
            if (CloseFrm != null)
            {
                CloseFrm(sender, e);
            }
        }
    }
}

MainForm为了显示主窗体（FormA）关闭，子窗体（FormB）也关闭。

public partial class MainForm: Form   
    {   
        public MainForm()   
        {   
            InitializeComponent();   
        }   
  
        private void button1_Click(object sender, EventArgs e)   
        {   
            FormA formA = new FormA();   
            formA.ShowDialog();   
        }   
    }  
public partial class MainForm: Form
    {
        public MainForm()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            FormA formA = new FormA();
            formA.ShowDialog();
        }
    }

摘自红色黑客联盟(www.7747.net) 原文：http://www.7747.net/kf/201007/52817.html